InAs is a direct, narrow band gap （0.354 eV） material with ultrahigh electron mobility, and is potentially a good optoelectronic device candidate in the wide UV-visible-near-infrared region. In this work we report t...InAs is a direct, narrow band gap （0.354 eV） material with ultrahigh electron mobility, and is potentially a good optoelectronic device candidate in the wide UV-visible-near-infrared region. In this work we report the fabrication of InAs nanowire-based photodetectors, which showed a very high photoresponse over a broad spectral range from 300 to 1,100 nm. The responsivity, external quantum efficiency and detectivity of the device were respectively measured to be 4.4 × 103 AW , 1.03 × 106%, and 2.6 × 1011 Jones to visible incident light. Time dependent measurements at different wavelengths and under different light intensities also demonstrated the fast, reversible, and stable photoresponse of our device. Theoretical calculations of the optical absorption and the electric field component distribution were also performed to elucidate the mechanism of the enhanced photoresponse. Our results demonstrate that the single-crystalline InAs NWs are very promising candidates for the design of high sensitivity and high stability nanoscale photodetectors with a broad band photoresponse.展开更多
A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV ...A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV irradiation, exhibiting long photochromic lifetime and good fatigue resistance. The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile. A new mechanism was put forward： salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form, enhancing the chelation of Cd（Ⅱ） and yielding the ring-opening rhodamine B part. Compared to other reported photochromic systems, this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.展开更多
The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventin...The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventing UV light from entering solar cells lowers the power conversion efficiency by reducing the photocurrent. The challenge is to improve UV stability without sacrificing efficiency. Here, we demonstrate the reduction of UV light-related negative effects from the perspective of spectral modification. By simultaneously introducing UV–visible downshifting and light trapping, perovskite solar cells can achieve a comparable efficiency of over 21% to that of an unmodified device. The optimized device obtains increased UV stability due to UV–visible downshifting. Different from other strategies, spectral modification externally alters the composition of incident light and improves UV stability without changing the internal device architecture, which is broadly applicable to perovskite solar cells with different structures. The present work may also find applications in other types of solar cells to boost the stability of devices exposed to UV light.展开更多
基金Acknowledgements This work was supported by the National Natural Science Foundation （Nos. 91123008, 51002059, 21001046）, the 973 Program of China （No. 2011CB933300）, and the Program for New Century Excellent Talents of the Universities in China （grant No. NCET-11-0179）. We thank the Analytical and Testing Center of Huazhong University of Science and Technology for measurements.
文摘InAs is a direct, narrow band gap （0.354 eV） material with ultrahigh electron mobility, and is potentially a good optoelectronic device candidate in the wide UV-visible-near-infrared region. In this work we report the fabrication of InAs nanowire-based photodetectors, which showed a very high photoresponse over a broad spectral range from 300 to 1,100 nm. The responsivity, external quantum efficiency and detectivity of the device were respectively measured to be 4.4 × 103 AW , 1.03 × 106%, and 2.6 × 1011 Jones to visible incident light. Time dependent measurements at different wavelengths and under different light intensities also demonstrated the fast, reversible, and stable photoresponse of our device. Theoretical calculations of the optical absorption and the electric field component distribution were also performed to elucidate the mechanism of the enhanced photoresponse. Our results demonstrate that the single-crystalline InAs NWs are very promising candidates for the design of high sensitivity and high stability nanoscale photodetectors with a broad band photoresponse.
基金financially supported by the National Natural Science Foundation of China(21175079 and 21375074)
文摘A photochromic rhodamine B-based material containing Cd（Ⅱ） as bridge was facilely prepared. The 4-methoxylsalicylalde hyde rhodamine B bydrazone Cd（Ⅱ） complex displayed unusual ring-open response upon 365 nm UV irradiation, exhibiting long photochromic lifetime and good fatigue resistance. The UV-induced ring-open of the complex led to a distinct color and fluorescence change in acetonitrile. A new mechanism was put forward： salicylaldehyde part in the complex underwent UV-promoted isomerization from enol-form to keto-form, enhancing the chelation of Cd（Ⅱ） and yielding the ring-opening rhodamine B part. Compared to other reported photochromic systems, this new photochromic material offered attractive new insights into the development of low cost photochromic materials with good performance.
基金supported by the National Natural Science Foundation of China (52025028, 51972218)the 1000 Youth Talents Plan+2 种基金the 333 High-level Talents Cultivation Project of Jiangsu Provincethe Six Talents Peak Project of Jiangsu Provincethe Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions。
文摘The stability of perovskite solar cells is an important issue to be addressed for future applications.Perovskite solar cells are vulnerable to exposure to UV light due to promoted chemical reactions.However, preventing UV light from entering solar cells lowers the power conversion efficiency by reducing the photocurrent. The challenge is to improve UV stability without sacrificing efficiency. Here, we demonstrate the reduction of UV light-related negative effects from the perspective of spectral modification. By simultaneously introducing UV–visible downshifting and light trapping, perovskite solar cells can achieve a comparable efficiency of over 21% to that of an unmodified device. The optimized device obtains increased UV stability due to UV–visible downshifting. Different from other strategies, spectral modification externally alters the composition of incident light and improves UV stability without changing the internal device architecture, which is broadly applicable to perovskite solar cells with different structures. The present work may also find applications in other types of solar cells to boost the stability of devices exposed to UV light.
